According to an example aspect of the present invention, there is provided an apparatus for a base station including at least one processing core, configured to cause the apparatus at least to define a first cluster of time-division duplex user equipments at least partly by including in the first cluster user equipments whose uplink signals may be received using a single first directional beamforming beam, determine a ratio of received signal strengths of a pair of user equipments in the first cluster, the pair including a first user equipment associated with the apparatus and a second user equipment associated with a neighbouring base station device, and responsive to the ratio fulfilling a predetermined condition, inform the neighbouring base station device of a scheduling plan of the first user equipment.